The present invention relates in general to anchoring systems, and more particularly, to an anchoring rail, and an anchorage system and method for attaching lining materials to a substrate or casing. Even more particularly, the present invention relates to an anchor rail and anchorage system for attaching and anchoring ceramic refractory tiles over a metallic process surface of a unit experiencing extreme service conditions, such as a fluidized catalytic cracking (FCC) cyclone or vessel.
The use of refractory lining materials, such as monolithic ceramic materials, in high-temperature, severe duty environments is known throughout the petrochemical and refractory industries. For example, ceramics have been used in fluid catalytic cracking (FCC) air grid nozzles, cyclone dustbowls and diplegs, fluffing and stripping steam rings, catalyst withdrawal lines, and the like. They have also been used in burner throats and flue gas diversion tiles in fired heater applications. Erosion tests comparing ceramic materials to more conventional extreme service refractory have shown the ceramics to have about five to ten times, or better, abrasion resistance.
xe2x80x9cInsertxe2x80x9d installations, such as cyclone cones and diplegs, have presented minimal problems in field applications due in part to, for example, the fact that geometry tends to keep the materials in place, relatively small diameters, etc. However, equipment with larger diameters and flat sections have traditionally been more problematic. This is due in part to problems associated with different coefficients of thermal expansion of the materials of the equipment casing, the anchor, and the refractory tile.
Cyclone linings and other extreme service refractory installations in, for example, FCC units, typically consist of Resco AA-22S, manufactured by Resco Products, Inc. of Norristown, Pa., which is a phosphate-bonded refractory with hex mesh anchoring systems. Numerous alternative castable refractory materials (e.g., Harbison-Walker Coral Plastic, Plibrico Pliram, etc.) have been tested with generally successful results. Although existing lining technology (primarily hex mesh and AA-22S) is fairly simple to install initially, it is difficult and expensive to repair.
Other conventional techniques for attaching ceramic refractory tiles to metallic substrates include, for example, using single imbedded metallic clips welded to attachment studs, using central anchor rails, and using edge-clip/ship-lap designs. Single clip/stud anchoring methods provide a positive attachment but only at one central location for each tile. High tile costs favor using fewer, larger tiles. However, a large tile with a single, centrally located attachment point has several disadvantages. Central anchor rails mandate the ability to slide the tile down the length of the rail, which requires manufacturing tolerances higher than normally associated with fabricated structures. Designs requiring that the tile be able to slide down the length of the centrally located rail also introduce repair difficulties as well. Alternatively, studs protruding from the back of the central anchor rail could pass through holes formed in the metallic substrate. The studs could subsequently be welded to the back of the substrate by depositing weld material into the resulting annular hole. However, this is a difficult fabrication method.
Certain edge-clip/ship-lap designs offer the flexibility of placing a tile and then a clip and so on. However, the edge clip/ship-lap tile design is such that a single edge failure leads to catastrophic failure of the entire lining.
Accordingly, there is a need for a reliable, low-cost solution to the conventional anchor and anchorage system problems that is easy to manufacture, install, maintain, and repair. Similar needs are mirrored in other industries having extreme service processes, such as for example, the petrochemical, refractory, construction, and mining industries.
The above described problems associated with prior art devices and techniques for securely anchoring ceramic refractory materials to units experiencing extreme service conditions, such as a FCC cyclones or vessels, are overcome by the present invention. The solutions described herein are applicable in other industries in which a refractory and/or erosion lining is needed for use in equipment operating in relatively extreme operation conditions and extreme service locations.
The present invention is directed to an anchoring rail for attaching a ceramic refractory material having a slot formed in each of two opposite sides to a substrate or casing. The anchoring rail includes an elongated web and a retention structure extending from the web. A bottom edge of the web is attached to a process surface of the substrate or casing. Preferably, the retention structure includes a plurality of perpendicularly extending tabs extending from the web and are constructed to fit within and engage a corresponding alignment structure on the ceramic refractory material. Preferably, the tabs are formed extending outward from a top portion of the web alternating between a first direction and a second opposite direction. In addition, the tabs preferably extend in both the first direction and the second opposite direction in a plane that is substantially perpendicular to a plane defined by the web.
The anchor rail is preferably formed by cutting or punching a template of the rail from a piece of sheet metal and then forming the template such that the anchoring rail has a web and alternating perpendicularly extending tabs extending from the web. The tabs preferably have one of a square or a rectangular shape, although other shapes are possible, such as a semi-circular, an elliptic, a dovetail, etc. The bottom edge is constructed to attach to the inner surface of the substrate or casing. The anchor rails are preferably attached to the metallic substrate using conventional welding techniques, such as stitch welding. The preferred alternating recesses formed between tabs helps facilitate the attachment of the anchoring rail to the substrate by allowing a welding apparatus access to the bottom edge of the rail.
The present invention is also directed to an anchorage system for securely attaching lining materials, such as ceramic refractory tiles, to a metallic substrate or casing. The anchorage system includes an anchoring rail, as described herein above, a plurality of ceramic refractory tiles, and a substrate or casing of a unit, piece of equipment, or service location.
According to one embodiment of the invention, the anchor system includes a plurality of anchor rails that are used to attach a ceramic refractory material, such as a plurality of ceramic tiles, to a metallic substrate of casing, such as the inner wall of a FCC cyclone or vessel.
Preferably the substrate or casing is a metallic material. The substrate can include one of a shell, a pressure vessel, a cyclone body, an equipment working surface, an inner diameter, an outer diameter, or any other surface that is exposed to a process characterized by high temperatures and/or high erosion.
The lining material preferably includes a ceramic refractory material, such as ceramic refractory tiles. The anchorage system includes a plurality of tiles arranged adjacently and having an anchoring rail disposed therebetween to locate and anchor the tiles to the process surface of the substrate. The tiles have a top surface that is exposed to the process and a bottom surface that covers the process surface of the substrate. Each tile includes an alignment structure formed in each tile. Preferably, the alignment structure includes a plurality of slots formed in each of two opposite sides of the tile. The slots are formed to receive and connectively engage the tabs of the anchoring rails. Preferably, each slot is an elongated slot that is formed proximate the center of each side and runs substantially the longitudinal length of the tile.
The slots separate each side into an upper tongue and a lower tongue on each side of the tile. A relief notch can be formed on the lower tongue proximate the bottom surface. The relief notch provides a relief for the weld bead formed along the bottom edge of the anchoring rail. In addition, the lower tongue is preferably cut back a distance equal to about half the thickness of the web to allow a clearance for the thickness of the web and to allow the upper tongues of adjacent tiles to butt-up against one another.
In addition, a closing strip can be used to close the gap between the final tiles. The closing strip is preferably made from of a conventional refractory material, such as hex mesh and AA-22, or equivalent. Preferably, the closing strip is located in the least erosive area for the particular installation or service location.
A further embodiment within the scope of the present invention is directed to a method of anchoring a ceramic refractory material, such as a ceramic tile, to a process surface of a metallic substrate, or casing, such as a FCC cyclone or vessel, to form a ceramic lined structure. In a preferred embodiment, the method includes attaching metallic anchoring rails to the inner wall of a casing of, for example a FCC cyclone or vessel, and then attaching ceramic tiles to the anchoring rails to form a ceramic lining over the inner surface of the casing.
In another embodiment, the present invention includes a method of building ceramic lined structures in which the ceramic lining is structurally anchored to a metallic substrate, or casing. This method includes welding an anchor rail in place, fitting a tile in place with its edge fitting around the anchor rail, welding another anchor rail in place against the edge of the previously fitted tile, and continuing on with another tile, then a rail, then a tile, etc. until a predetermined surface area of the device is lined with tiles.
This method may preclude completing an entire circle around the inner circumference surface of a circular device. Accordingly, for devices having a circular shaped surface to be lined completely around its circumference, the final space between the first and last tile can be filled in with a closing strip of traditional refractory/anchorage system. Alternatively, the final tile may be slid into place on the first and final rail from the end. Preferably, the anchorage system of the present invention is used to line the most critical areas (e.g., those areas experiencing the most extreme operating conditions) of a particular piece of equipment and the traditional refractory/anchorage system is used in an area experiencing the least extreme conditions.
The lining method works equally well for new construction and repair areas during a plant shutdown. The design provides continuous anchorage along the edge of each tile while still allowing the metallic substrate to expand and slide relative to the ceramic tiles.